Cyclamate

Cyclamic acid and its sodium and calcium salts are food additives commonly
termed "cyclamates." Cyclamates are used in over 50 countries as intense
sweeteners in a range of food categories. Sodium cyclamate is about 30 times
sweeter than sucrose in dilute solution. It was initially marketed as table-top
sweetener for diabetics. In 1968, the FDA discovered toxicity of sodium
cyclamate in rats (bladder carcinogenicity) and prohibited its use in food.

Cyclamates produce cyclohexylamine metabolites which can be formed from
unabsorbed cyclamates by the intestinal flora in certain individuals.
Cyclohexylamine is very toxic compared to sodium cyclamate.